Currently, gas chromatography (GC) and ion mobility spectrometry (IMS) combination technology (GC-IMS) is used to pre-separate a sample, based on the prominent separating performance of GC for complex components, to separate a mixture into single components, and transfer them to an IMS detector for detection. It has been confirmed that such combination technology extends the resolution of IMS detection for chemical components by increasing the retention time information of GC, achieves higher detection limit and widens linear dynamic range. The GC-IMS combination technology has thus rapidly developed in recent years. However, a conventional GC analysis process has difficulty meeting the requirements of fast detection in situ as a complete GC analysis spends more than ten minutes and needs a huge oven to obtain high temperature conditions.
In addition, IMS is currently widely equipped with radioactive β source, which may radiate high-energy primary electron (63Ni:67 keV, 3H:18 keV). The existing apparatus is configured to directly introduce a separated sample into an ionization area, where part of the sample is broken by the high-energy β ray into fragment ions, or is ionized as molecular ions with positive charge. On the one hand, the fragment ions may result in an increased wave crest of reactive ion (by monitoring RIP, it may be mainly (H2O)nH+ in a positive mode, or it may be mainly O2−(H2O)2 in a negative mode), which may disturb a baseline and decrease resolution of IMS detection. Particularly, during detection of biomacromolecule such as protein molecular or nucleic acid, an electron ionization source will render more complex fragments, which will form a map that is hard to be identified. For this reason, it is difficult for a GC-IMS spectrometer to be applied in the field of detecting organic macromoleculars. On the other hand, the fragment ions or molecular ions with positive charge may be reacted with reactive ions to obtain an unresolvable ion spectrum, in which the lines in the spectrum are disordered and are troublesome to analyze. It is desired to provide accurate IMS detection.